Genetic variability within Helicobacter pylori

One of the striking characteristics of the human gastric pathogen Helicobac ter pylori is extensive genetic diversity between different strains. During the last years, intensive research using genomic, molecular genetic and po pulation genetic approaches has permitted to quantitate the diversity in H. pylori, to define its characteristics, and to understand the mechanisms th at generate diversity in this global pathogen. This review summarizes the r ecent developments in this rapidly moving field and discusses the significa nce of genomic heterogeneity and nucleotide sequence diversity in the conte xts of H. pylori epidemiology and pathogenesis.